Genetic test fingers viral, bacterial infections

Method could help doctors treat children's fevers

By differentiating between bacterial and viral fevers, a new test may help doctors decide whether to prescribe antibiotics.

Fevers are a common symptom of many infectious diseases, but it can be difficult to tell whether viruses or bacteria are the cause. By measuring gene activity in the blood of 22 sick children, Gregory Storch, a pediatrician and infectious disease researcher at Washington University in St. Louis and colleagues were able to distinguish bacteria-sparked fevers from ones kindled by viruses. The activity of hundreds of genes changed as the children’s immune systems responded to the pathogens, but the team found that gauging the response of just 18 genes could correctly distinguish between viral and bacterial infections about 90 percent of the time. The gene activity test could also determine, for viral infections, which specific microbes caused the illness, the team reports July 15 in the Proceedings of the National Academy of Sciences.

Storch’s technique isn’t ready for the clinic; for one thing, it takes days to do the assay and doctors need answers much sooner. But Storch says he’s working to develop a test that could be used in hospitals and doctor’s offices.

The research is a step toward improving diagnosis, says Octavio Ramilo, a pediatric infectious disease specialist at Ohio State University and Nationwide Children’s Hospital in Columbus, who has done similar work. In the future, being able to quickly determine the cause of fevers should help prevent unnecessary antibiotic prescriptions, he says. Antibiotics kill bacteria, but do nothing to fight viruses. Improper antibiotic use has been linked to bacterial resistance to the drugs.

Citations

X. Hu et al. Gene expression profiles in febrile children with defined viral and bacterial infection. Proceedings of the National Academy of Sciences published online July 15, 2013. www.pnas.org/cgi/doi/10.1073/pnas.1302968110